1. Field
Embodiments relate to an organic light-emitting display device.
2. Description of the Related Art
In general, flat display devices may be classified into an emissive type and a non-emissive type. The emissive type display devices may include, for example, flat cathode ray tubes, plasma display panels (PDPs), and electroluminescent devices. The non-emissive type display devices may include liquid crystal displays (LCDs). The electroluminescent devices have wide viewing angles, excellent contrasts, and rapid response speeds and thus have recently been highlighted as next generation display devices. Such electroluminescent devices may be divided into inorganic electroluminescent devices and organic electroluminescent devices according to materials for forming an emission layer.
An organic electroluminescent device is a self-luminous display that electrically excites fluorescent organic compounds and emits light and has been highlighted as a next generation display device which may be driven at low voltage, easily made thin, has a wide viewing angle, and a rapid response speed.
The organic electroluminescent device includes an emission layer that is formed of an organic material and is interposed between an anode and a cathode. As an anode voltage and a cathode voltage are respectively applied to the anode and the cathode, holes injected from the anode move to the emission layer through a hole transport layer (HTL) and electrons move from the cathode to the emission layer through an electron transport layer (ETL) so that the holes and the electrons recombine in the emission layer to form excitons.
The excitons change from an excited state to a ground state so that fluorescent molecules of the emission layer radiate, thereby forming an image. In a full-color type organic electroluminescent device, pixels that emit red R, green G, and blue B color are included to realize a full color.
In such an organic electroluminescent device, pixel-defining layers are respectively formed at both end portions of an anode. Then, after a predetermined opening is formed in the pixel-defining layer, an emission layer and a cathode are sequentially formed on the anode that is exposed to the outside by the opening.